1. Field of the Invention
The present invention relates in general to a system and method for determining a pivot center and radius using a least squares approach, and in particular to determining a pivot center and radius of rotation for a dispenser in an agricultural application.
2. Background of the Invention
There are various types of crop irrigation techniques depending on how the water obtained from the water source is distributed within the field. In general, the goal is to supply the entire field uniformly with water, so that each plant has the amount of water it needs. While ditch irrigation, terracing and overhead irrigation have been and continue to be used as irrigation techniques, center pivot irrigation has become a popular method by which to irrigate crop fields due in part to the efficiencies of the planting in crop circles.
Center pivot irrigation consists of several segments of pipe (usually galvanized steel or aluminum) joined together and supported by trusses mounted on wheeled towers with sprinklers positioned along its length. The system moves in a circular pattern and is fed with water from the pivot point at the center of the arc. Most center pivot systems now have drops hanging from a u-shaped pipe called a gooseneck attached at the top of the pipe with sprinkler heads that are positioned a few feet (at most) above the crop, thus limiting evaporative losses. Drops can also be used with drag hoses or bubblers that deposit the water directly on the ground between crops. The crops are planted in a circle to conform to the center pivot. This type of system is also known as LEPA (Low Energy Precision Application).
It is desirable to control the application of, e.g., water or chemicals—to such a field as described above—in an efficient manner so as to minimize the amount of time taken and the amount of water (or other applicant) needed to cover the field. In order to cover a given circular field in an optimal manner, the pivot must be anchored at the center of the field, and the arm adjusted to match the radius of the field. This is not a trivial matter given that such farming fields can be several acres in area. Heretofore, to determine the center of a crop circle and anchor an irrigation arm in such a large field, the terrain would have to be carefully surveyed by the farmer. However, this can be an inefficient and time consuming procedure.
Accordingly, there is a need for an improved system and method for determining the center and irrigation radius for a center pivot irrigation system.